Alpha-fetoprotein on Amniotic Fluid

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Amniotic fluid alpha-fetoprotein (AF-AFP) testing at 15-30 weeks gestation screens a fetus for an increased risk of open neural tube or open body wall defects. AF-AFP analysis can be used to further evaluate abnormal serum AFP levels identified during maternal serum screening.

Ind​ications

Elevated AF-AFP levels are associated with a number of fetal defects, including open neural tube defects, such as spina bifida and anencephaly, and open ventral wall defects, such as omphalocele and gastroschisis.

AF-AFP levels are especially indicated in women at an increased risk for a neural tube defect (NTD) or open ventral wall defect, including:

Patients on valproic acid anti-seizure medication

Insulin dependent diabetic patients

Previous pregnancy or child with a NTD or open ventral wall defect

Ultrasound indications of a NTD or open ventral wall defect

Methodology

AF-AFP results and interpretation are provided to the Colorado Genetics Laboratory by Associated Regional University Pathologists, Inc. (ARUP).

Specimen Requirements

No additional specimen is needed for AF-AFP testing on specimens submitted for AF-AFP and amniotic fluid chromosome analysis. Colorado Genetics Laboratory withdraws the appropriate amount of amniotic fluid supernatant from the submitted specimen and refers this test to ARUP. The sample must be accompanied by a completed a Test Request Form​ including pertinent clinical and family history, and the gestational age at the time of specimen collection.

Acetylcholinesterase on Amniotic Fluid

Acetylcholinesterase (AChE) testing is performed as a reflex confirmation test on individuals with an abnormal amniotic fluid alpha-fetoprotein (AF-AFP) level of 2.0 multiples of the mean (MOM) or greater.

Indications

AChE testing should also be utilized in certain clinical situations where there is an elevated risk for a neural tube defect (NTD) or open ventral wall defect, including:

Patients on valproic acid anti-seizure medication

Insulin dependent diabetic patients

Previous pregnancy with a NTD

Ultrasound indications of a NTD or open ventral wall defect

Methodology

Results and interpretation of the AChE are provided to the Colorado Genetics Laboratory by Associated Regional University Pathologists, Inc. (ARUP) and the Foundation for Blood Research (FBR).

Specimen Requirements

No additional specimen is needed for AChE testing on specimens submitted for AF-AFP/AChE and amniotic fluid chromosome analysis​. Colorado Genetics Lab withdraws the appropriate amount of amniotic fluid supernatant from the submitted specimen and refers this test to ARUP. The sample must be accompanied by a completed Test Request Form​, including pertinent clinical and family history, and gestational age at the time of specimen collection.​​​​